Forging apparatus and method

ABSTRACT

IN FORGING MATERIALS BETWEEN A MOVABLE RAM AND A DIE ASSEMBLY ON AN ANVIL, PROVIDING A CONTINUOUS LOAD ABSORBING HYDRODYNAMIC LIQUID FILM BETWEEN THE DIE ASSEMBLY AND THE ANVIL TO REDUCE DETRIMENTAL STRESS CONDITIONS. DETECTING MISALIGNMENT OF THE RAM BY PHOTOCELL SENSING MEANS AND CONTROLLING A HYDRAULIC CYLINDER WHICH SLIDABLY ADJUSTS THE POSITION OF THE DIE ASSEMBLY ON THE ANVIL INTO ALIGNMENT WITH THE RAM.

Jaw 19, 1971 E. J. SEBASTIAN FORGING APPARATUS AND METHOD Filed April 17, 1967 f SUFPL V ELE crac HYDRAULIC CaNro/.e

United States Patent O 3,555,865 FORGING APPARATUS AND METHOD Edmund J. Sebastian, 6563 Shabbona Road, Indian Head Park, Ill. 60525 Filed Apr. 17, 1967, Ser. No. 631,323

Int. Cl. B213' 7/46' U.S. Cl. 72-21 7 Claims ABSTRACT OF THE DISCLOSURE In forging materials between a movable ram and a die assembly on an anvil, providing a continuous load absorbing hydrodynamic liquid film between the die assembly and the anvil to reduce detrimental stress conditions. Detecting misalignment of the rarn by photocell sensing means and controlling a hydraulic cylinder which slidably adjusts the position of the die assembly on the anvil into alignment ywith the ram.

INTRODUCTION BACKGROUND, SUMMARY, AND BRIEF DESCRIPTION OF THE DRAWINGS It is a general object of the invention to reduce or eliminate certain machine component failures which occur in the operation of forging machines.

In conventional drop forge hammer machines, a metal billet is forged into a desired configuration by positioning the billet between mating dies and applying repeated blows to the billet until the desired shape is obtained. Very large impact forces are involved. Conventionally, the lower die is rigidly attached to a sow block which in turn is rig-idly held to an anvil. The upper die is fastened to a ram, and the ram is reciprocally moved vertically by a piston rod.

In general, the most frequent failures in drop forge hammer machines occur in the piston rod by complete rupture of the rod in the area where it makes contact Iwith the ram. Next most frequent failures occur in the ram and in the sow block.

Failures in the piston rod are believed to be attributable to a column effect caused by the forces applied to either end of the rod upon impact. This produces flexing of the piston rod, which causes it to work harden and to eventually rupture by fatigue failure. The ram is subject to similar but reactive-type stress conditions.

The sow block undergoes deformation due to the repeated absorption of high energy impact forces. As the sow block deforms, its contact with the anvil is restricted to only localized areas determined by the form and extent of the deformation. In this condition, the so-w block cannot absorb impact loads uniformly, and concentrated stress conditions arise which cause its eventual failure. Conventional forging machines provide only a metal-tometal contact between the sow block and the anvil, and the sow block is rigidly held in place by mechanical wedging arrangements. As the sow block absorbs repeated blows from the ram, this wedging is jarred loose and must be manually readjusted.

The present invention greatly reduces the frequency of the above described forging machine component failures by supporting the sow block on a hydrodynamic film which provides uniform load absorption regardless of the deformation of the sow block, and by aligning the upper and lower die assemblies at the instant of forging contact by movement of the sow block on the hydrodynamic film. Metal-to-metal contact between the anvil and the sow block is eliminated, and the severe shock effects produced by the forging ram on the sow block are hydraulically absorbed. The invention may be used with either new or existing machines.

3,555,865 Patented Jan. 19, 1971 ICC Further objects, features and advantages of the invention pertain to the particular arrangement and structure whereby the above mentioned aspects of the invention are attained. The invention will be better understood by reference to the following description and to the drawings forming a part thereof, wherein:

FIG. l is a perspective schematic view of an exemplary embodiment of the invention;

FIG. 2 is a cross-sectional view taken along the line 2 2 of FIG. l; and

FIG. 3 is a perspective View of the anvil shown in FIG. l.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT In FIGS. l through 3, there is shown a forging machine 10 in accordance with the present invention. For clarity of description, it may be seen that the preferably conventional components have been illustrated schematically. It will be appreciated that all of the components of the forging machine 10 may be conventional other than as specifically described herein.

The forging machine 10 here includes an anvil 12 supporting and holding a lower die assembly 14. The lower die assembly 14 is preferably an integral unit consisting of the desired shaping die (not shown) and a supporting sow block 16, or merely the sow block 16. The sow block 16 absorbs the forging forces'and transmits these forces to the anvil 12. An upper die assembly 18 includes a ram 20 vertically overlying the lower die assembly 14. The ram 20 is vertically reciprocally operated against the lower die assembly 14 by a piston 22 through a connecting piston rod 24. The ram is held in general alignment in its vertical movement by a forge frame 26 of the forging machine.

`Considering in greater detail the sow block 16, it may be seen that it is preferably a thick metal block or slab having a large horizontal lower surface parallelly overlying a correspondinghorizontal surface 28 on the anvil 12. Preferably, the sow block 16 is mounted in a recess in the anvil 12 between an opposing parallel and generally vertical pair of side walls 30. The sow block 16 is restrained from movement in one horizontal direction by the pair of side walls 30. However, the sow block 16 is not restricted from movement in a second horizontal direction at right angles thereto. Contrary to conventional practice, the sow block 16 is not rigidly held in place, or attempted to be held in place, by a mechanical wedge arrangement in this second horizontal direction.

Referring particularly to FIG. 3, it may be seen that there is provided in the anvil 12 beneath the surface 28 underlying the sow block 16 a plurality of fluid conduits 32. These conduits 32 may be machined intoa conventional anvil 12. The fluid conduits 32 preferably have outlets only at a plurality of spaced orifices 34 at the anvil surface 28. The orifices 34 are thus positioned to provide a continuous hydrodynamic film of fluid between the sow block and its supporting anvil surface 28 when fluid is applied under pressure to the fluid conduits 32. Referring to FIG. l, it may be seen that a conventional hydraulic power supply 36 is connected to the fluid conduits 32 to provide a continuous flow of hydraulic fluid under pressure thereto. It will be appreciated that a conventional hydraulic return system `(not shown) is also preferably provided to return the hydraulic `fluid to the hydraulic power supply 36.

The fluid provided between the contiguous horizontal surfaces of the anvil and the sow block is preferably a conventional fireproof hydraulic fluid. The fluid flow between the two surfaces constitutes a hydrodynamic film with a load bearing capability supporting the sow block 16 and preventing metal-to-metal contact between these two surfaces. This hydrodynamic film insures uniform load absorption regardless of the area of the load application or the deformation of the sow block. It hydraulically absorbs the severe shock effects produced by the impact of the forging ram 20 on the material being worked. Detrimental stress conditions and permanent deformation of the sow block are reduced or eliminated.

The sow block 16 is slidably adjustable on the hydrodynamic film with respect to the anvil 12 in the horizontal direction parallel the side walls 30. Adjustment means are provided for moving the sow block 16, and thus the entire lower die assembly 14, in this direction so as to align the lower die assembly 14 with the upper die assembly 18. Accurate positioning of the two die assemblies to avoid misalignment as the material is being worked is important n preventing detrimental stress conditions in all cornponents and particularly in the piston rod 24. Misalignment occurs primarily in the two horizontal directions, and with the forging machine the misalignment in one of these two directions is eliminated.

The upper and lower die assemblies are aligned and maintained in alignment herein by sensing any misalignment in the ram while the rarn is moving into engagement with the lower die assembly by moving the sow block on its supporting hydrodynamic film an equal distance. This alignment is maintained continuously throughout the downward movement of the ram 20 so as to insure alignment at the point of impact regardless of the vertical height of the billet or workpiece.

Referring to FIGS. l and 2, and particularly to FIG. 2, there is illustrated a sensing means 38 for continuously detecting misalignment of the upper die assembly 18 in the horizontal direction of movement of the sow block 16. It may be seen that there is provided a projection 40 fastened to and moving with the ram 20. The projection 40 has an even vertical outer edge 42. Fastened to the frame 26 and partially enveloping the projection 40 is a photocell assembly 44 including a conventional variable electrical output photocell 46 and an opposing conventional light source 48. It may be seen that the photocell 46 and the light source 48 are positioned and spaced so that the projection 40 lies therebetween and partially blocks the light from the light source 48 received by the photocell 46. Any movement of the ram 20 in the horizontal direction of the projection 40 moves the outer edge 42 of the projection 40 either further into or out of the path of the light between the light source 48 and the photocell 46. Accordingly, a correspondingly lesser or greater amount of light will strike the photocell 46. Thus, the electrical signal present on the electrical leads 50 of the photocell 46 is a direct analog indication of the horizontal movement of the ram 20.

It may be seen that the leads 50 from the photocell assembly 44 are connected to and control an electrohydraulic controller 52 which may be of conventional construction. The controller 52 is supplied with hydraulic fluid under pressure from the hydraulic power supply 36. The electrohydraulic controller 52 selectively controls the pressure and volumetric rate of flow respectively applied to its two hydraulic output lines 54. The lines 54 are connected respectively to the two opposite ends of a conventional hydraulic control cylinder 56 to control the position of a hydraulic piston 58 therein. The cylinder 56 is aligned parallel the horizontal direction of movement of the sow block 16. The piston 58 is directly connected to the sow block 16 and thereby controls the position of the sow block.

The electrohydraulic controller 52 may be conventionally initially adjusted so that the piston 58 initially positions the lower die assembly 14 into alignment with the upper die assembly 18. Any subsequent misalignment of the ram 20 is sensed by the sensing means 38 and causes an unbalanced output of the electrohydraulic controller 52 and thereby correctively moves the sow block 16. Preferably the control system is a closed loop system.

4 A cylinder position feedback signal is provided to the electrohydraulic controller. It will be appreciated that other suitable position sensing members may be employed in place of the photocell assembly 44. For example, a linear differential transformer might be used.

Considering the operation of the forging machine 10, it will be apparent from the above description that the continuous iiow of load bearing incompressible uid is applied under pressure between the die assembly and the anvil in a hydrodynamic film throughout the forging process. It will also be apparent that the lower die assembly is continuously slidably adjusted on the anvil into alignment with the ram as the ram is moved toward the lower die assembly. As the ram is forced downward by the action of the piston 22, its horizontal movement is sensed by the sensing means 38. The electrical signal from the photocell 46 is transmitted to the electrohydraulic controller 52 which converts this electrical signal to a corresponding proportional hydraulic output transmitted to the double acting control cylinder 56. The cylinder 56 thus moves the sow block in the same direction by an equal distance to bring the lower die assembly into alignment with the upper die assembly. This alignment process occurs automatically throughout the vertical movement of the ram 20.

It may be seen that there has been described herein an apparatus and method for forging which provides improved forging with greatly reduced component failures, and which may be employed in either new or existing forging operations. The apparatus and method described herein are presently considered to be preferred; however, it is contemplated that further variations and modifications within the purview of those skilled in the art can be made herein. The following claims are intended to cover all such variations and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In an impact machine for forging materials between a vertically reciprocal ram and an underlying die assembly including a sow block, said sow block having a large surface area overlying a corresponding surface area on an anvil, wherein said sow block is restricted from movement by said anvil in one horizontal direction and movable on said anvil in a second horizontal direction, the improvement comprising:

a hydraulic power supply for providing a continuous flow of incompressible fluid to said anvil;

said anvil having a plurality of fiuid conduits therein connecting with said hydraulic power supply;

said anvil having a spaced plurality of small orifices in its surface underlying said sow block and connecting with said hydraulic power supply through said conduits to provide a continuous load absorbing hydrodynamic film of said incompressible uid between said sow block and said anvil and wherein impact forces imposed by said ram are absorbed; and

said sow block being slidably adjustable on said hydrodynamic film in said second horizontal direction on said anvil into alignment with said ram.

2. The machine of claim 1 including sensing means for sensing movement of said ram in said second horizontal direction and drive means controlled by said sensing means for moving said sow block an equal distance to said movement of said ram to maintain alignment between said underlying die assembly and said ram.

3. In a machine for forging materials between a movable aligned ram and a die assembly on an anvil, the improvement comprising:

a load bearing film of incompressible uid between said die assembly and said anvil, v said die assembly being slidable on said lm with respect to said anvil,

and adjustment means for slidably adjusting the position of said die assembly on said anvil into alignment with said ram,

said adjustment means including sensing means for sensing a change in alignment of said ram and drive means controlled by said sensing means for moving said die assembly a distance equal to said change in alignment of said ram.

`4. The machine of claim 3 wherein said sensing means includes a photocell adjacent said ram, the output of which is varied by the change in alignment of said ram, and said drive means includes a hydraulic piston connected to said die assembly.

5. A process for forging materials between a movable ram and a die assembly on an anvil, comprising:

applying a continuous flow of load bearing incompressible lluid under pressure between the die assembly and the anvil in a hydrodynamic lm,

and slidably adjusting the position of the die assembly on the anvil into alignment with the ram as the ram is moving toward the die assembly.

6. The process of claim 5 wherein the uid is simultaneously applied at multiple spaced areas under the die aembly.

7. The process of claim 5 wherein the misalignment 6 of the ram is continuously sensed as said ram moves toward the die assembly and the die assembly is continuously slidably adjusted in accordance with said sensed misalignment of the ram.

References Cited UNITED STATES PATENTS 1,275,258 8/1918 Holmes 72-447 1,474,066 11/1923 Brown 72-447 2,788,862 4/1957 Langer 184-6 3,218,108 11/1965 Sazavsky 308-5 3,355,990 12/1967 Thurn 308-5 FOREIGN PATENTS 840,751 7/ 1960 Great Britain 184-6 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner U.S. Cl. X.R.

P240?) Ummm STfrzafs 11i-"mii Vir @Frisia CERTEFCATE OF CORRECTCN Patent No. 3,555,865 i Dated I January 19, 1971 Inventor(s) EDMUND J. SEBASTIAN It is certified that error appears in the above-identified pal-'Tent and that said Letters Patent are hereby corrected as -sbown below:

Column 3, line 214, 'after "assembly" `iri'sert -and..

Signed and sealed this 1 st day` gf June 1'9.71

(SEAL) Attest: t A

, EDWARD Mmmrcrrsmm.' r l -WILLIAM-j'.' SGHUYLER, .n Attesting Officer Y A Gommieoner of Patent 

